<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
		<script type="text/javascript">
			window.onload = function(){
				var btn = document.getElementsByTagName("input")[2];
				btn.onclick = function(){
					console.log("onclick");
				}
				btn.onmouseenter = function(){
					console.log("onmouseenter");
				}
			}
		</script>
	</head>
	<body>
		<input type="button" value="1" />
		<input type="button" value="1" />
		<input type="button" value="1" />
	</body>
</html>
